Disk drives are widely used in computers, consumer electronics and data processing systems for storing information in digital form. A disk drive typically includes one or more storage disks and one or more sliders. Each slider includes a read/write head that transfers information to and from the storage disk, and one or more air bearing surfaces. With a contact start-stop (CSS) type disk drive, the slider rests on the storage disk when the storage disk is not rotating.
Rotation of the storage disk drags air under the slider. The amount of air dragged under the slider during rotation of the storage disk varies according to the rotation rate of the storage disk. When the rotation rate is greater than a take-off velocity, the slider begins to ride on an air bearing with the read/write head spaced apart a distance from the storage disk that is commonly referred to as a “fly height”.
The fly height of the slider can vary according to the rotation rate of the storage disk. For example, when the storage disk is rotating below the take-off velocity, insufficient air is being dragged under the slider and the slider is contacting the storage disk. The fly height of the slider is also influenced by the one or more air bearings on the slider. Accordingly, the value of the take-off velocity will vary according to the design of the slider.
During non-rotation of the storage disk, no air flow is generated and the slider rests in a landed position on the surface of the storage disk. During start-up of the disk drive, the rotation rate of the storage disk ramps up from zero to desired operational rotation rate of the storage disk. With this design, during start up, the storage disk is dragged against the slider until the rotation rate of the storage disk ramps beyond the take-off velocity.
Unfortunately, dragging the storage disk against the slider causes wear and damage to the slider and the storage disk. This can result in inaccurate data transfers, the loss of data and/or failure of the disk drive.